81157296 has 80 divisors (see below), whose sum is σ = 229949568. Its totient is φ = 24460800.

The previous prime is 81157291. The next prime is 81157313. The reversal of 81157296 is 69275118.

It is not an unprimeable number, because it can be changed into a prime (81157291) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 148095 + ... + 148641.

Almost surely, 2^81157296 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81157296, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (114974784).

81157296 is an abundant number, since it is smaller than the sum of its proper divisors (148792272).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81157296 is a wasteful number, since it uses less digits than its factorization.

81157296 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 850 (or 844 counting only the distinct ones).

The product of its digits is 30240, while the sum is 39.

The square root of 81157296 is about 9008.7344283201. The cubic root of 81157296 is about 432.9547641763.

The spelling of 81157296 in words is "eighty-one million, one hundred fifty-seven thousand, two hundred ninety-six".